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authorMel Gorman <mel@csn.ul.ie>2007-07-17 04:03:13 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:22:59 -0700
commit396faf0303d273219db5d7eb4a2879ad977ed185 (patch)
tree96cb64fd6713ef7a924f4f878e259aea781f079a /kernel/sysctl.c
parent2a1e274acf0b1c192face19a4be7c12d4503eaaf (diff)
Allow huge page allocations to use GFP_HIGH_MOVABLE
Huge pages are not movable so are not allocated from ZONE_MOVABLE. However, as ZONE_MOVABLE will always have pages that can be migrated or reclaimed, it can be used to satisfy hugepage allocations even when the system has been running a long time. This allows an administrator to resize the hugepage pool at runtime depending on the size of ZONE_MOVABLE. This patch adds a new sysctl called hugepages_treat_as_movable. When a non-zero value is written to it, future allocations for the huge page pool will use ZONE_MOVABLE. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. [akpm@linux-foundation.org: various fixes] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2ce7acf841ae..48dae075d5c2 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -826,6 +826,14 @@ static ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "hugepages_treat_as_movable",
+ .data = &hugepages_treat_as_movable,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &hugetlb_treat_movable_handler,
+ },
#endif
{
.ctl_name = VM_LOWMEM_RESERVE_RATIO,